Many personal care products currently available to consumers are directed primarily to improving the health and/or physical appearance of the skin. Among these skin care products, many are directed to delaying, minimizing or even eliminating skin wrinkling and other histological changes typically associated with the aging of skin or environmental damage to human skin.
Extrinsic or intrinsic factors may result in the thinning and general degradation of the skin. For example, as the skin naturally ages, there is a reduction in the cells and blood vessels that supply the skin. There is also a flattening of the dermal-epidermal junction which results in weaker mechanical resistance of this junction. See, for example, Oikarinen, “The Aging of Skin: Chronoaging Versus Photoaging,” Photodermatol. Photoimmunol. Photomed., vol. 7, pp. 3-4, 1990.
Existing therapies useful for reducing or eliminating fine lines and wrinkles are often invasive, cumbersome and/or expensive. Such examples include exfoliation (through laser resurfacing, chemical peels, dermabrasion and cold ablation); implants (comprising silicone, microlipoinjection, gore-tex and collagen); and muscle relaxants such as Botulinum. Plastic surgery may also be employed for removing wrinkles.
Existing noninvasive methods of reducing fine lines and wrinkles in subjects generally involve the application of a topical cream or other composition. These methods may utilize many of a variety of ingredients, however, the penetration of these ingredients past the stratum corneum is limited. Therefore, the effect that these creams or compositions have on the collagen network is negligible due to limited penetration and delivery.
Iontophoresis is a technique that has been used to enhance the penetration of topically applied drugs or other substances on skin and mucous membranes through the use of electric current. This technique is cumbersome, in part, because it requires placing separate electrodes on a person, one for delivery of an electric current, the other required to ground the electric current. Examples of such use include: Gangarosa et al., J. Pharm. Sci. (October 1979) 67(10):1439-1443; Gangarosa et al., Ear. Nose & Throat (December 1982) 61:30-41; Gangarosa et al., Proc. Soc. Exper. Bio. & Med. (1986) 181(3):476; Tyle, P., Pharm. Res. (1986) 3(6):318-326; Sloan et al., J. Am. Acad. Derm. (October 1986) 15(4, pt 1):671-684; Sloan et al., Drug Design & Delivery (1989) 4:1-12; and Kost, J. et al., U.S. patent application Ser. No. 20010056255 (filed Dec. 27, 2001) (iotophoresis combined with ultrasound); and Keller et al., U.S. Pat. No. 6,048,545. In addition, in examples where iontophoresis contemplates the use of liposomes, these are exclusively phospholipid-based liposomes. Relatedly, the use of pulsed current to load molecules into a membrane vesicle in cultured cells has been described in U.S. Pat. No. 5,964,726.
Accordingly, there is still a need to overcome difficulties that are encountered in therapeutic or experimental administration of compositions which have a positive effect on a subject's collagen support network and which do not involve cumbersome and invasive alternative methods of wrinkle reduction.